Re: Load balancing between an RAC database cluster and Top Link

Holger Baer <holger.baer_at_science-computing.de> wrote in message news:<bv3dtv$4t2$1_at_news.BelWue.DE>...
> Greg Collett wrote:
> > All,
> >
> > We are designing an environment which is comprised of 3 database
> > servers clustered together using RAC 10g. Connecting to the database
> > is an Oracle Application Cluster of 4 App Servers running toplink.
> > Currently the connection is facilitated through XML using oracle jdbc
> > drivers.
> >
> > My question: In order to properly load balance the calls to the
> > databse servers, do I require a hardware level load balancer between
> > the Application tier and the Database tier?
> >
> > My understanding is that Oracle chares the db cache between the 3
> > servers, and I believe it does load balancing between the servers as
> > well. However, the jdbc connection on the app servers currently points
> > at 1 database machine directly, and if that machine went down, the app
> > could not connect to the RAC cluster (without a manual change). Is
> > there a non-hardware solution to get around this?
> >
> > I am new to some of this and would appreciate any guidance.
> >
> > Thanks,
> > Greg
>
> Sorry, I don't have 10g specific information (don't know if them that
> have are allowed to share them yet with us ;-) ) but the load balancing/
> transparent application failover mechanisms for RAC in 9i requires
> the usage of OCI. So if you use the thick drivers, you should be able
> to use TAF; the thin drivers bypass the OCI-Layer so if Oracle doesn't
> provide them with support for TAF in 10g then there is no way I guess.
>
> HTH
>
> Holger

Thanks Holger. I know that the developers hit a number of issues using the thick (OCI) client. I have heard rumours that you can use the thin client and add the redundancy information to the connection url. Something like this:

url="jdbc:oracle:thin:@(DESCRIPTION=
(LOAD_BALANCE=on)(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=host1) (PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=host2)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=service_name)))"

Thoughts?

Greg

p.s. Thanks all for the discussion on the necessity of HA and the risk-analysis thoughts. This is a mission-critical application which costs $$$ whenever we suffer any outage. Received on Wed Feb 11 2004 - 15:46:38 CST